Method of testing adequacy of cells in a specimen

ABSTRACT

The present invention relates to an appartus and method for use in pre-screening or determining the adequacy of target cells in specimen prior to conducting further diagnostic testing or analysis of the specimen. More specifically, the present invention concerns a device and method which uses light scatter techniques to detect the presence of a target cell in a specimen.

BACKGROUND OF THE INVENTION

The present invention relates to an apparatus and method for use inpre-screening or determining the adequacy of target cells in a specimenprior to conducting further diagnostic testing or analysis of thespecimen. More specifically, the present invention concerns a device andmethod which uses light scatter techniques to detect the presence of atarget cell in a specimen.

SUMMARY OF THE INVENTION

Prior to conducting an analysis or testing of a cell specimen, it isimportant to insure that an adequate amount of target cells are presentin the specimen. This is particularly true with respect to pap smearspecimens.

It is estimated that about 180 million pap smears are performed in theUnited States annually with an estimated 33% of all specimens originallycollected containing insufficient target cells—ectocervical or squamouscells. This results in an inability to properly analyze the specimen andin a tremendous loss in time and money. Typically, not only must apatient reschedule another office visit to provide a second specimen, asecond charge is often incurred to obtain the second specimen with noguarantee that enough target cells were again obtained. Thus, there is aneed to provide a method and apparatus which provides a quick andefficient system to pre-screen specimens to determine if adequate targetcells are present.

The present invention solves this lack of pre-screening by providing adevice and method which analyzes a specimen through the use ofsubmitting the specimen to a light scatter analysis. Through thistechnique, a specimen may be analyzed for the presence of sufficientquantities of a target cell. In addition, the technique would also allowa specimen to be analyzed for the presence of target cells which mayadversely affect the diagnostic procedure to be used.

DESCRIPTION OF THE DRAWINGS

These and other features, objects and advantages of the presentinvention will become apparent from the following description anddrawings wherein like reference numerals represent like elements inseveral views, and in which:

FIG. 1 shows a sample analysis using light scatter to locate a pluralityof predetermined target cells.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Set forth below is a description of what are currently believed to bethe preferred embodiments or best examples of the invention claimed.Future and present alternatives and modifications to the preferredembodiments are contemplated. Any alternates or modifications in whichinsubstantial changes in function, in purpose, in structure or in resultare intended to be covered by the claims of this patent.

The present invention may be useful in pre-screening or determining thepresence of target cells in sufficient quantities prior to subjectingthe specimen to further testing. As explained above, screening specimensfor adequate amounts of target cells or the presence of target cellswhich are adverse to a procedure, while a patient is still at a medicalfacility, will save both time and money.

To do this, the present invention uses a technique commonly referred toas light scatter. In this technique, a cell is subjected to lightapplied at a predetermined orientation. Because each cell has a specificmorphology, when illuminated, the cell's morphology will cause light tobe scattered in a predetermined pattern in both a forward and sidedirection. Thus, for each target cell of interest, a predetermined lightscatter pattern can be established in a forward direction, sidedirection or both forward and side directions using flow cytometry andother similar techniques which are known to those of skill in the art.

Thus, in using the present invention, after a specimen is obtained, itcan be quickly subjected to a light scatter technique to determine ifadequate target cells are present for further testing purposes or ifadverse target cells are present. As explained above, using thistechnique would increase the efficiency and cost-effectiveness of anytesting procedure including, but not limited to, pap smear testing.

More specifically, to measure the adequacy of liquid based cervicalcytology specimens such as in a pap smear specimen, 1 mL of the sample(usually 10 mL) routinely collected in industry standard preservatives(Cytyc, TriPath) may be pelleted by centrifugation at 500-1000×g andresuspended in 300 uL of phosphate buffer saline (PBS), pH 7.4. Thesample is then run in a flow cytometer or the like for analysis offorward light scatter and side (90°) light scatter. Ectocervical(columnar) cells, endocervical (squamous) cells, neutrophils, andnon-cellular material/debris are resolved into 4 cellular populations asshown in FIG. 1 using a log scale rather than a linear scale. Thepresence of both ectocervical and endocervical cells would indicate anadequate specimen. Conversely, the absence or the low amount of apredetermined light scatter pattern for a target cell would indicatethat an inadequate specimen had been obtained and the collectionprocedure should be repeated. This process would take approximately 10minutes.

While the preferred embodiments of the present invention have beenillustrated and described, it will be understood by those of ordinaryskill in the art that changes and other modifications can be madewithout departing from the invention in its broader aspects. Variousfeatures of the present invention are set forth in the following claims.

What is claimed is:
 1. A method of pre-screening a specimen to determinean adequate number of squamous (ectocervical) cells, columnar(endocervical) cells, neutrophils, and noncellular material forsubsequent liquid based cytology analysis comprising: a. analyzing saidliquid based cytology specimen using light scatter to quantify thenumber of different cells in said specimen; and b. determining if thequantity of squamous (ectocervical) cells versus columnar (endocervical)cells versus neutrophils versus noncellular material using the resultsof said light scatter is sufficient for liquid based cytology analysis.2. The method of claim 1 wherein said light scatter characteristic isforward light scatter.
 3. The method of claim 1 wherein said lightscatter characteristic is side light scatter.
 4. The method of claim 1wherein said light scatter characteristic is both side and forward lightscatter.
 5. A method of pre-screening a specimen to determine anadequate number of at least one target cell for subsequent liquid basedcytology analysis comprising: analyzing said liquid based cytologyspecimen using light scatter to quantify the number of at least onetarget cell in said specimen; and determining if the quantity of atleast one target cell in said specimen is sufficient for liquid basedcytology analysis using the results of said light scatter.
 6. The methodof claim 5 wherein the target cell is an ectocervical cell.
 7. Themethod of claim 5 wherein the target cell is an endocervical cell. 8.The method of claim 5 wherein the specimen is to be used in a cervicalcancer screening test.
 9. The method of claim 5 wherein said lightscatter is forward light scatter.
 10. The method of claim 5 wherein saidlight scatter is side light scatter.
 11. The method of claim 5 whereinsaid light scatter is both side and forward light scatter.
 12. A methodof pre-screening a specimen to determine an adequate number of at leastone target cell in a cervical cytology specimen for subsequent liquidbased cytology analysis comprising: analyzing said liquid based cervicalcytology specimen using light scatter to quantify the number of at leastone target cell in said specimen; and determining if the quantity of atleast one target cell in said specimen is sufficient for liquid basedcytology analysis using the results of said light scatter.
 13. Themethod of claim 12 wherein the target cell is an ectocervical cell. 14.The method of claim 12 wherein the target cell is an endocervical cell.15. The method of claim 12 wherein said light scatter is forward lightscatter.
 16. The method of claim 12 wherein said light scatter is sidelight scatter.
 17. The method of claim 12 wherein said light scatter isboth side and forward light scatter.